/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.paimon.flink.clone;

import org.apache.paimon.table.sink.ChannelComputer;

/**
 * {@link ChannelComputer} for distributing {@link CloneFileInfo} records into SnapshotHintOperator
 * for recreate snapshot hints.
 *
 * <p>{@link CloneFileInfo}s are distributed by target table name, so the creation of snapshot hints
 * of each table is handled by only one parallelism.
 */
public class SnapshotHintChannelComputer implements ChannelComputer<CloneFileInfo> {

    private static final long serialVersionUID = 1L;

    private int numChannels;

    @Override
    public void setup(int numChannels) {
        this.numChannels = numChannels;
    }

    @Override
    public int channel(CloneFileInfo record) {
        int hsh = 0;
        for (int i = 0; i < record.getTargetIdentifier().length(); i++) {
            hsh = (hsh * 131 + record.getTargetIdentifier().charAt(i)) % numChannels;
        }
        return hsh;
    }
}
